I'm a developer, so no hardware expert, but I have this running stable at 1.2GH/s. It's running in an air conditioned comms room (with permission, at work), so no elec costs, but with a 1KW PSU, it would be about 0.9 UK units p/h (at about 12p/unit, so about £80-£90 per month). I've also set my GPU fans to all run 100% all the time (noise isn't a problem and I don't want it to overheat), I realise this will wear the bearings in the fans out quicker, but it seems to me that I'm already late to the btc party and running it at full tilt now makes sense.

I'm running Windows 7 x64, with GUIMiner and there are a few gotchas that I sorted and are the main point of this post.

I setup the computer to automatically logon as me (and to go to an empty screensaver after a minute requiring a password to unlock it) and set my Bios to automatically start the system if the system loses power. I added a shortcut to GUIMiner in the Startup folder for my user account, but this kept causing the system to hang. I realised it was because the Catalyst drivers hadn't fully loaded yet (or something along those lines), so I made a batch file that started GUIMiner after a 30 second delay. I'm sure there are other ways of solving this (such as running the app as an NTService), but this was mine...

Simply put the following in a .bat file in your startup folder and after 30 seconds it will start the software. Just set all your pools to autostart and you're good.

Another thing that got me on Windows 7 was Power Management. I'm used to Sever OSes, which don't shut down after 1 hour, etc. so this caught me out and I had to go back and sort it out the first time I left it running. Set Windows 7 Power Management to High-Performance and make sure you don't let it put anything to sleep.

Because it's just a standard PC with no remote management I also plugged it into one of these that I had, so I can reset it remotely, which will automatically start it up and start it mining again, should it hang, BSOD, etc.

One last thing was that connecting to it with RDP caused the gfx drivers to crash twice (I've not tried since then) and I lost the 2nd card each time (rebooting sorted), so I gave up on that and used teamviewer instead, which seems to work a treat for remote access.

Indeed. With my experience of graphics drivers causing BSODs, I reckon that could save me a few late night drunken trips on my bicycle down to the comms room to keep my new hobby going... There are other solutions (possibly cheaper, for 1 PC etc.), but that's one I had that wasn't being used anymore.